1. Field of the Invention
This invention relates to a resin molding device, resin molding method and resin molded product, more specifically, a resin molding device, resin molding method and resin molded product capable of guiding a sink to an optional place to perform a precise molding.
2. Description of the Prior Art
In an optical writing optical system such as laser type digital copying machine, laser printer, facsimile device or the like, an optical element such as laser beam imaging rectangular lens or mirror having various correcting apparatuses or the like is used.
In recent years, such an optical element is changed in material from glass to plastic due to the demand for lower cost of product and variously diversified in shape as thick wall, thin wall, longitudinally uniform wall and non-uniform wall lenses according to required optical performances.
In resin molding, it is generally difficult to precisely arm a molded product having a thick wall part or non-uniform wall part, and a failure phenomenon of transfer precision by sink or contraction distribution is apt to occur in a part requiring functional precision or a part requiring transfer of fine surface shape.
Therefore, it was proposed in the past to press the reverse side or vicinity of a resin part requiring transfer precision to a transfer surface side by the pressure of fluid or gas in molding (refer to Japanese Patent Application Laid-Open No. 10-156861).
However, this method requires a high-pressure fluid EURO and an expensive and complicated facility such as a control device for controlling the pressure and introducing timing of the fluid from the high-pressure source or the like because the reverse side or vicinity of the resin part requiring transfer precision is pressed to the transfer surface side by the pressure of fluid or gas, and also has the problem of poor availability in the use of a pressure-gas as the fluid, which has many restriction items up to the introduction of the facility including the necessity of permissions for the use of high-pressure gas, the setting position of device and the like.